package com.it.park.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.lang.RandomStringUtils;

public class ServletCode extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * Constructor of the object.
	 */
	public ServletCode() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	@Override
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	@Override
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doPost(request, response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	@Override
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		int width = 80;
		int height = 35;
		String s = RandomStringUtils.random(4, true, true);
		// 保存入session,用于与用户的输入进行比较.
		// 注意比较完之后清除session.
		HttpSession session = request.getSession(true);
		  session.setAttribute("authCode", s);
		response.setContentType("images/png");
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		   
		ServletOutputStream out = response.getOutputStream();
		 BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
		 Graphics g = image.getGraphics();
		// 设定背景色
//		   g.setColor(getRandColor(200, 250));
		   g.fillRect(0, 0, width, height);
		// 设定字体
		   Font mFont = new Font("华文新魏", Font.HANGING_BASELINE, 23);// 设置字体
		   g.setFont(mFont);
		   // 画边框
		   // g.setColor(Color.BLACK);
		   // g.drawRect(0, 0, width - 1, height - 1);
		   
		   // 随机产生干扰线，使图象中的认证码不易被其它程序探测到
		   g.setColor(getRandColor(160, 200));

		// 生成随机类
		   Random random = new Random();
		   for (int i = 0; i < 155; i++) {
		    int x2 = random.nextInt(width);
		    int y2 = random.nextInt(height);
		    int x3 = random.nextInt(12);
		    int y3 = random.nextInt(12);
		    g.drawLine(x2, y2, x2 + x3, y2 + y3);
		   }
		// 将认证码显示到图象中
		   g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
		   
		// 第一位指随机数，第二位指随机数左右位移，第三位指随机数上下位移
		   g.drawString(s, 10, 28);
		   
		// 图象生效
		   g.dispose();
		   // 输出图象到页面
		   ImageIO.write(image, "png", out);
		   out.close();
		   System.out.println(s);
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	@Override
	public void init() throws ServletException {
		// Put your code here
	}
	
	// 给定范围获得随机颜色
	 private Color getRandColor(int fc, int bc) {
	 
	  Random random = new Random();
	  if (fc > 255)
	      fc = 255;
	  if (bc > 255)
	      bc = 255;
	  int r = fc + random.nextInt(bc - fc);
	  int g = fc + random.nextInt(bc - fc);
	  int b = fc + random.nextInt(bc - fc);

	  return new Color(r, g, b);
	 }
}
